Ok the obvious stuff seems to have gone so its time to start voting! In time honoured fashion of only upvoting things under 20 and downvoting over 20, I've gone for the following:
Downvote: Hwacha. So I already have crossbowman to kill units. What I need is a unit that can take cities. Oh wait the siege unit doesn't work properly anymore?

. Destroyer of the alternative wide specialist style I love so much with Korea.
Upvote: Pictish Warrior. The faith bonus happens exactly when you want it, after which the anti mounted bonus returns. The pillage bonus is great when these guys beast it in the early medieval as super pikes, and then still provides benefit in the late game. The degredation of the line is no real concern as they've already done their work by then. If I can't get by without UU's late game something has gone horribly wrong earlier. Early UU's are useful every single game and are much more important in each game.